The rising demand for healthcare services urges the implementation of the most effective practices by healthcare institutions,[1] and the average length of stay (ALOS) is the measure considered to evaluate hospital efficiency by researchers, doctors, and policymakers around the world.[2]

The number of days spent at a hospital significantly impacts both the patient and the hospital. Decreased time spent in the hospital can lower the possible risk of opportunistic infections for patients and is often linked to better quality of treatment.[3] In addition to this, reduced LOS results in decreased medical fees for patients. Quicker discharges contribute to lesser congestion in the hospital's emergency department (ED),[4] allowing more availability of hospital beds and resources for incoming patients and in turn boosting hospital revenue.[3]

Over the past decade, several researches have been conducted on the ALOS in different patient groups. These include studies analyzing LOS in patients undergoing coronary artery surgery,[5] patients having hip injuries,[6] intensive care unit patients,[7],[8] and patients having pulmonary disease.[3],[9]

The LOS has been observed to vary across different countries. The data for the average number of days patients admitted to hospitals each year from 2007 to 2017 are presented in [Figure 1]. These data were obtained from the Organization for Economic Cooperation and Development.{Figure 1}

Interpreting the variations between LOS of patients across the different countries requires taking into account factors, such as the difference in patient management by hospitals across the countries as well as the difference in patient profiles of each population.[3]

In addition to assessing differences between countries, it is also beneficial to assess the trends in hospitalization across the years within the same country. A longitudinal cohort study targeting the US population has used the National Inpatient Sample to assess long stay hospitalizations occurring for 10 years from 2002 to 2012. Based on the data collected, even though prolonged hospitalizations accounted for only 2% of all admissions, it represented 14% of all hospital days accounting for more than 20 billion dollars per annum. Results show that over time, prolonged hospitalizations were due to younger individuals and specifically those belonging to minority groups living in urban settings.[10] It was also concluded that over the 10-year duration, inpatient mortality in the US had decreased from 14.5% to 11.6% (P < 0.001).[10]

Furthermore, a study performed in England analyzing data through the National Health Service (NHS) records from 1997 to 2014 confirmed that the LOS for primary knee replacement decreased from 16 (95% confidence interval [CI] 14.9–17.2) days during 1997 to just 5.4 (5.2–5.6) days in 2014. The decrease in LOS is considered to be most likely a result of the increased efficiency of the healthcare system.[11]

Many previously performed studies have suggested a strong association between age and increased length of patient stay.[12],[13] A recently performed study, however, has produced results which disregard age as a factor influencing LOS and contradict the previous studies.[14] This indicates the need for more studies focusing on the impact of age on length of patient stay.

Low socioeconomic status and belonging to a minority race have also been linked to longer LOS. However, there is a lack of research regarding the impact that these factors have on LOS, and to make stronger associations, further research is needed.[4]

When evaluating LOS, hospital management policies must also be kept into consideration as a study performed using the NHS in the UK found that LOS varies greater across different hospitals than with different doctors working for at the same organization.[15]

Moreover, a study by Riguzzi et al. found that teaching hospitals are subjected to 15% increased LOS at the ED as compared to nonteaching hospitals all year round (95% CI = 11%–20%). Median LOS at nonteaching hospitals is 140 (interquartile range [IQR] = 81–232) min while median LOS at teaching hospitals is 165 (IQR = 94–276) min. This study however cannot be generalized to all teaching hospitals as it defines teaching hospitals as those having more than 25% of their patients looked over by residents. The study also did not take into account the difference between teaching hospitals having emergency medicine (EM) residents and those having non-EM residents working in the ED.[16]

Another study by Esmaeili et al. concluded that patient stay in the emergency room (ER) exceeding 24 h could be attributed to delayed decision-making by doctors and patients with complicated presenting complaints and delayed transferal of patients from the ER to their assigned departments by staff. The results of this study however are not confirmed and are only subjected to inference as the study was a cross-sectional study overlooking just one ED.[17]